Upload with your visit at least one (1) photo on which the owner of this waymark can see that you have been there.
That is easy done by a photo of de surroundings on which also the ANWB Mushroom is present.

Write down with every photo the ANWB Mushroom number - City name in the 'Image Caption'.
The photo is and remains always identifiable by this unique ANWB number and City name.